P3D optics of stereo viewers [resend]

[erker@xxxxxxxxxxxxxx (Greg Erker)]

Didn't make it the first time AFAI could see - Greg E.

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[re: the cost of "perfect viewer lenses"]

  The B&H web page shows Peak Professional
Anastigmatic Loupes.  See:
http://www.bhphotovideo.com/photo/loupes/allpurpose.html

  It claims to be 7x and has a field of view
of 41 mm (which should be enough for the
diagonal of a mounted 2x2 slide since the
mount cuts a little bit off). In any
case it would be plenty for 7 perf slides.

  7x probably means the focal length is
about 42 mm (if they are using the 1+250/FL
method). Pretty close to the Red Button in FL.

  They also claim "Insures critical
sharpness from edge to edge and corner to
corner, due to the high degree of field and optical
aberrations. Ordinary magnifiers are corrected only
for the center image. The optical design of these
loupes enable viewing from one inch above the eye
piece, so that the entire image area may be viewed
without moving one's head."

  The cost is $129.95 (each). Throw in another $60
for an Alan Lewis type mahogany box and another
$40 (guessing) for colour corrected fluorescent
lighting. The total is $360, plus your building/
assembly time.

  Let us know how it works out after you have
built it. :)

---

  For medium format stereo, a couple of Schneider
4x loupes should do the job:
http://www.bhphotovideo.com/photo/loupes/214.html

  They are $224 each and the estimated FL is 83 mm
which is nearly ortho for 80 mm camera lenses.

  So the total damage, with case and lighting would
be about $550 or maybe a bit more.

  I'm sure this would be a wonderful viewer, but would
it be 15x as good as the one I made using $15 achromats
from American Science & Surplus?
http://www.angelfire.com/ca/erker

---

  More seriously, if anyone ever does build a viewer
using good photographic loupes I/we'd like to hear
about it. Especially how it compares against common
viewers like the RB or KII (field curvature, edge
sharpness, pincushion, contrast etc.)

Thanks - Greg E.



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